11/21/2023 0 Comments Npn transistor![]() A simple way to remember how to properly bias a transistor is to observe the NPN or PNP elements that make up the transistor. At the same time the second PN junction (base-collector junction) is biased in the reverse, or high-resistance, direction. For the transistor to function in this capacity, the first PN junction (emitter-base junction) is biased in the forward, or low-resistance, direction. To use the transistor as an amplifier, each of these junctions must be modified by some external bias voltage. The action at each junction between these sections is the same as that previously described for the diode that is, depletion regions develop and the junction barrier appears. Just as in the case of the PN junction diode, the N material comprising the two end sections of the NP N transistor contains a number of free electrons, while the center P section contains an excess number of holes. With this information fresh in your mind, let's proceed directly to the NPN transistor. ![]() This concept is the basic theory behind how the transistor amplifies. In this manner, a power gain would be obtained across the crystal. Thus, if a crystal were to contain two PN junctions (one forward-biased and the other reverse-biased), a low-power signal could be injected into the forward-biased junction and produce a high-power signal at the reverse-biased junction. By using the Ohm's law formula for power (P = I 2 R) and assuming current is held constant, you can conclude that the power developed across a high resistance is greater than that developed across a low resistance. In turn, a reverse-biased PN junction is comparable to a high-resistance circuit element. ![]() You should recall from an earlier discussion that a forward-biased PN junction is comparable to a low-resistance circuit element because it passes a high current for a given voltage.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |